how to apply parent directory and current directory variable together

Question

there is a .dir-locals in parent directory

((nil (global-auto-revert-ignore-buffer . t)))

and there is a .dir-locals in current directory

((nil (tags-file-name "TAGS")))

but when I visit files in current directory only tags-file-name directory variable are applied. but when I visit another subdirectory without .dir-locals, global-auto-revert-ignore-buffer are applied.

Could apply both directory variables in current directory?

Thanks!

Answer 1

No, there is no provision (at least as at Emacs 24.5) for additionally continuing to look for and process ancestor .dir-locals.el files after a nearer one has been located.

However, if it makes sense for your scenario, you can remove your "current directory" file and specify all the variables in the parent .dir-locals.el file.

Keys which are strings specify sub-directories; and the variables beneath that are set in addition to (or perhaps overriding) the ones in the top-level specifications.

See C-hig (emacs) Directory Variables, which provides the following example:

     ((nil . ((indent-tabs-mode . t)
              (fill-column . 80)))
      (c-mode . ((c-file-style . "BSD")
                 (subdirs . nil)))
      ("src/imported"
       . ((nil . ((change-log-default-name
                   . "ChangeLog.local"))))))

This sets ‘indent-tabs-mode’ and ‘fill-column’ for any file in the
directory tree, and the indentation style for any C source file.  The
special ‘subdirs’ element is not a variable, but a special keyword which
indicates that the C mode settings are only to be applied in the current
directory, not in any subdirectories.  Finally, it specifies a different
‘ChangeLog’ file name for any file in the ‘src/imported’ subdirectory.